73066599
Oct 21, 1975
Jun 29, 1976
COMMUNICATION EQUIPMENT SUCH AS MICROPHONES, EARPHONES, HEADSETS, WITH AND WITHOUT PREAMPLIFIERS AND WITH AND WITHOUT ELECTRET CONDENSERS OR CERAMIC TRANSDUCERS, WIRELESS INDUCTION EARPHONES, REMOTE SWITCH ASSEMBLIES, COMBINED MICROPHONE AND RECEIVER, AND BATTERY HOLDERS
Electrical and Scientific Apparatus